【小米OJ-小米兔的轨迹】顺时针蛇形矩形

import java.util.*;

public class Main {
    static int dr[]={0,1,0,-1};///向左加，向右减
    static int dc[]={1,0,-1,0};///向下加，向上减
    static int arr[][];
    static int n,m;
    public static void main(String [] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        m = sc.nextInt();
        arr = new int[n + 10][m + 10];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                arr[i][j] = sc.nextInt();
         System.out.print(arr[0][0]);
         arr[0][0]=-1;
        int t=0;
        int r=0;
        int c=0;
        int j=0;
        while(++t<n*m){
            while(true){
                int x = r+dr[j];
                int y = c+dc[j];
                if(panduan(x,y)&&arr[x][y]!=-1){
                    System.out.print(" "+arr[x][y]);
                    arr[x][y]=-1;
                    r=x;
                    c=y;
                    break;
                }
                j++;
                if(j>=4) j-=4;
            }
        }
    }
    static boolean panduan(int r,int c){
        return r>=0 && r<n && c>=0 &&c<m;
    }
}